JP5072786B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker that detects the temperature and cooks the cooked rice in the inner pot.

  In the conventional rice cooker, when white rice in the menu is selected by a menu key, a control program corresponding to the white rice is executed. First, in the preheating process, the rice and water, which are the cooked rice, are heated to raise the temperature, and until the temperature detected by the bottom temperature sensor reaches a predetermined temperature (for example, 62 ° C), the detected temperature reaches 62 ° C. Turn off heating. Thereafter, by controlling the heating based on the temperature detected by the bottom temperature sensor, the temperature is maintained at 62 ° C. until a predetermined time (for example, 10 minutes) elapses from the start of preheating, and the process proceeds to the rice cooking process when 10 minutes have elapsed. In the preheating process, the temperature detected by the lid temperature sensor is lower than the temperature detected by the bottom temperature sensor, and the degree of increase is very moderate.

  In the rice cooking process, heating is performed until the temperature detected by the bottom temperature sensor reaches a predetermined temperature (for example, 88 ° C.) from 62 ° C. by continuous heating. In addition, the time from the start of the rice cooking process until the detected temperature of the bottom temperature sensor reaches 88 ° C. is measured, the amount of rice cooking is determined based on this result, and the energization rate is determined from the amount of rice cooking. Even in this process, the temperature detected by the lid temperature sensor is lower than the temperature detected by the bottom temperature sensor, and the rate of increase is very moderate. In the next step, heating is performed according to the energization rate determined in the previous step. Moreover, the time from the rice cooking process start is continued from the previous process, and boiling of cooked rice is determined.

  The detection temperature of the bottom temperature sensor reaches to 100 ° C in a short time from the start of this process, but this is due to partial boiling etc. at the bottom of the cooked rice, and at this point the whole cooked rice is still in a boiling state. However, it is not reliable to determine boiling based only on the temperature detected by the bottom temperature sensor. On the other hand, the temperature detected by the lid temperature sensor rises slowly after the start of this process so that the entire cooked rice starts to boil and steam is generated vigorously so that the steam is filled in the inner pot. Then it starts to rise rapidly. Therefore, it becomes possible to accurately determine the boiling of the cooked rice by catching a sudden rise in the temperature detected by the lid temperature sensor. For example, a predetermined temperature (for example, 90 ° C.) in a sudden rise in the temperature detected by the lid temperature sensor is detected and determined to be boiling, and the process proceeds to the next step. Moreover, the amount of rice cooking is determined based on the timing results from the start of the rice cooking process to this point, the energization rate is determined from the amount of rice cooking, and heating is continued at the energization rate. When there is no moisture in the inner pot, the temperature at the bottom of the inner pot suddenly rises and the temperature detected by the bottom temperature sensor reaches the rice cooking completion temperature (for example, 124 ° C.), the heating is turned off and the process proceeds to the steaming process.

  In the steaming process, it starts timing for a certain time (for example, 12 minutes), waits for the detected temperature of the bottom temperature sensor to drop to a predetermined temperature (for example, 110 ° C), and starts heating again when 110 ° C is detected. Continue heating to 124 ° C. When 124 ° C. is detected, the heating is turned off, and the steaming process is completed after a certain period of time.

JP 61-222415 (page 2-5, FIG. 6-7)

  In the above-mentioned conventional rice cooker, characteristic changes or failures of components occur due to cooking of rice during actual use, heating of the heater at the time of heat retention, humidification due to steam generated during rice cooking or moisture adhering to the inner pan, etc. was there. For example, there are problems such as attachment of a temperature sensor composed of a thermistor or the like for detecting the temperature of the lid or the bottom of the inner pan, changes in the constants of electrical components, attachment of a heater provided on the body or lid. In that case, the rice cooking performance and the heat insulation performance were deteriorated. As a result, there are problems such as being unable to cook delicious rice, or being unsavory rice with poor heat retention. In addition, there was concern about smoke and fire due to overheating due to temperature detection failure.

  The present invention was made in order to solve the above-mentioned problems, and it is possible to prevent in advance that it becomes impossible to cook delicious rice, or it becomes unsavory rice with poor heat retention, It is another object of the present invention to provide a rice cooker that can prevent in advance the danger of smoke or fire due to overheating due to temperature detection failure.

  The rice cooker according to the present invention includes an inner pot that contains cooked rice, a heating means that heats the inner pot, a lid temperature sensor that detects the temperature in the inner pot, and a bottom temperature sensor that detects the temperature of the bottom of the inner pot. And a control means for controlling the heating means according to a preset program to cook the cooked rice in the inner pot, and the boiling of the cooked rice in the inner pot from the detection temperature of the lid temperature sensor every time rice is cooked by the control means Boiling control means for determining the presence or absence of abnormality of the rice cooker body, and the control means from the start of rice cooking to the detection of boiling each time boiling of the cooked food is detected by the boiling determination means The average value is calculated from the acquired time, and the abnormality determination means determines that there is an abnormality when the difference between the time and the average value is out of a predetermined range.

  In the present invention, every time boiling of the cooked rice in the inner pot is detected, the time from the start of cooking to the detection of boiling is obtained, and the average value is calculated from the obtained time, and the time and the average value The lid is determined to be abnormal when the difference is outside the specified range, so the lid is generated by cooking during actual use, heating during heat retention, humidification by steam generated during cooking or moisture attached to the inner pan, etc. It becomes possible to determine the deterioration of the rice cooking performance and the heat retaining performance due to the mounting failure such as the floating from the temperature sensing part of the temperature sensor. As a result, it is possible to prevent in advance problems such as being unable to cook delicious rice or becoming unsavory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.

Embodiment 1 FIG.
1 is a cross-sectional view showing the structure of a rice cooker according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing the configuration of the rice cooker according to Embodiment 1. As shown in FIG.

  In FIG. 1, the induction coil 6 which is a heating means of the rice cooker is supported by the coil base 7 of the protective frame 3 and is provided with a side induction coil 6a disposed so as to face the bottom corner of the inner pot 2. The bottom induction coil 6b is disposed so as to face the bottom of the inner pot 2. The bottom temperature sensor 10 is made of, for example, a thermistor, is attached through the central portion of the coil base 7, contacts the bottom of the inner pot 2 by the elastic force of the spring 11, and the temperature of the cooked rice stored in the inner pot 2. Is detected indirectly. The lid temperature sensor 19 is composed of, for example, a thermistor, is attached so as to penetrate the inner lid 17 and protrude from the lid radiator plate 14 to the inner pan 2 side, and detects the ambient temperature inside the inner pan 2.

  The protective frame 3 described above has an opening for accommodating the inner pot 2 and is constituted by an upper frame 3 a, a side heat dissipating plate 5 to which a body heater 4 is attached, and a coil base 7. The inner pot 2 is a bottomed cylindrical container whose outer surface is made of a magnetic metal, and a flange portion for suspending the upper portion of the protective frame 3 is formed on the periphery of the opening. The ferrite 8 is formed so as to cover the side induction coil 6 a and the bottom induction coil 6 b of the induction coil 6, and is supported by a ferrite base 9 attached to the coil base 7. The ferrite 8 is provided so that the magnetic flux generated from the side induction coil 6a and the bottom induction coil 6b does not leak to the outside.

  The lid 12 is supported by a hinge portion 3b formed integrally with the protective frame 3 via a shaft 13 so that the upper portion of the main body 1 can be opened and closed. A lid heat radiating plate 14 is attached to the lower part of the inner surface of the lid body 12, and a lid heater 15 is attached to the inner surface of the lid radiating plate 14. An operation panel 16 having a liquid crystal display unit 16a and a key input unit 16b (see FIG. 2) is provided on the front side inclined portion of the main body 1. The key input unit 16b is provided with a rice cooking key for starting cooking, a reservation key for setting a reservation time, an hour key and a minute key for setting the current time, and the like. The inner lid 17 is detachably attached to the lower surface of the lid body 12, and a packing 18 that closes in contact with the inner pot 2 when the lid body 12 is closed is disposed on the outer periphery thereof. In the vicinity of the protective frame 3 on the operation panel 16 side, the circuit board 20 provided with the control circuit 30, the data storage unit 34, the comparison value storage unit 35 and the like shown in FIG.

  As shown in FIG. 2, the control circuit 30 includes a microcomputer, for example, and includes a control unit 31, a boiling determination unit 32, and an abnormality determination unit 33. The control means 31 performs each process of heat insulation from rice cooking according to the control program stored in the memory | storage part (ROM) which is not shown in figure. That is, the induction coil is energized and the inner pot 2 is induction-heated to cook rice. Moreover, whenever the boiling determination means 32 detects the boiling of cooked rice, the control means 31 acquires the time from a rice cooking start to boiling detection, and calculates an average value from the acquired time. The aforementioned time and average value are stored in the data storage unit 34 for each amount of cooked rice. The average value is repeatedly calculated a predetermined number of times (for example, 10 times) for each amount of cooked rice. The boiling determination means 32 determines boiling of the cooked rice in the inner pot 2 every time the control means 31 cooks rice. The abnormality determination unit determines that there is an abnormality when the time acquired by the control unit 31 is out of a predetermined range with respect to the average value. This predetermined range is a constant set corresponding to the amount of cooked rice, and is stored in advance in the comparison value storage unit 35 for each amount of cooked rice. The time, average value, and predetermined range described above will be described later.

Next, in the rice cooker comprised as mentioned above, the rice cooking operation | movement of initial use and the rice cooking operation | movement at the time of the malfunction generation | occurrence | production by long-term use are demonstrated, referring FIG.
FIG. 3 is a diagram showing a correlation between a temperature curve and rice cooking power in the rice cooking operation of the rice cooker according to the first embodiment. In addition, the temperature curve of the continuous line shown in a figure shows the temperature change of the inner pot 2 bottom part by the detection of the bottom temperature sensor 10, and the temperature curve of a broken line shows the change of the atmospheric temperature in the inner pot 2 by the detection of the lid temperature sensor 19. Show. Moreover, among the temperature curves of the lid temperature sensor 19 indicated by a broken line, one curve is a temperature change at the initial use of the rice cooker, and the other curve is a temperature change at the time of occurrence of a malfunction (during deterioration) due to long-term use. It is. Moreover, the temperature curve and rice cooking electric power shown in a figure are correlation diagrams when cooking a certain amount of rice cooking.

  The above-mentioned problems are caused by changes in the characteristics of components, malfunctions, etc. due to heater heating during rice cooking or heat retention in actual use of a rice cooker, humidification due to steam generated during rice cooking or moisture adhering to the inner pot 2, etc. This is the case. For example, a thermistor for detecting the temperature of the lid 12 or the bottom of the inner pot 2, a change in the constants of electrical components, a malfunction of the body heater 4 or the lid heater 15, and the like.

  First, the rice cooking operation of initial use is demonstrated. Here, the rice cooking operation | movement at the time of selecting white rice as a menu similarly to the conventional rice cooker is demonstrated.

  When white rice is selected and the rice cooking key is turned on, the control means 31 of the control circuit 30 executes a control program corresponding to the selected white rice. First, the preheating process is started, the induction coil 6 is energized, the inner pot 2 is induction-heated, and the rice and water that are the cooked rice are heated to raise the temperature. Then, the control means 31 determines whether or not the detected temperature of the bottom temperature sensor 10 has reached a certain temperature (for example, 62 ° C.), and when the detected temperature of the bottom temperature sensor 10 has reached 62 ° C., the induction coil 6. The induction heating of the inner pot 2 is stopped by turning off the energization. Then, the energization to the induction coil 6 is controlled so that the temperature detected by the bottom temperature sensor 10 is maintained at 62 ° C., and the process proceeds to the rice cooking process when a predetermined time (for example, 10 minutes) has elapsed since the start of preheating. The purpose of this preheating process is to promote water absorption of rice, to compensate the temperature of the cooked rice relative to the water temperature and temperature, and to make the temperature distribution uniform regardless of the amount of cooked rice. The temperature detected by the lid temperature sensor 19 in the preheating process is lower than the temperature detected by the bottom temperature sensor 10, and the degree of temperature rise is very moderate.

  When the control means 31 enters the rice cooking process, the induction coil 6 is energized continuously, and the inner pot 2 is induction-heated until the temperature detected by the bottom temperature sensor 10 reaches a predetermined temperature (for example, 88 ° C.) from 62 ° C. In addition, it measures the time from the start of the rice cooking process until the detected temperature of the bottom temperature sensor 10 reaches 88 ° C., determines the amount of rice cooking based on this result, determines the energizing rate from this rice cooking amount, and determines the inner pot. 2 is induction heated. Even in this step, the detected temperature of the lid temperature sensor 19 is lower than the detected temperature of the bottom temperature sensor 10, and the degree of temperature rise is very moderate.

  In the case of a rice cooker cooked at 10 go, the amount of rice cooked is 10 steps from 1 go to 10 go, and the time T1 until the detected temperature of the bottom temperature sensor 10 reaches from 62 ° C. to 88 ° C. (not shown) Z)) is divided into 10 stages according to the characteristics for each amount of cooked rice. For example, when the value of T1 is 500 seconds or more, it is determined to be 10 go, and when it is 150 seconds or less, it is determined to be 1 go, and the interval is divided according to the characteristics for each amount of cooked rice. And the range which has the value of T1 is determined, and the amount of rice cooking is determined. The energization rate is set in advance corresponding to each amount of cooked rice, and the induction heating time is adjusted within a certain period (for example, 64 seconds). The purpose of adjusting the energization rate is to make the cooking time substantially constant even if the amount of cooked rice is different. For example, 10 seconds is 64 seconds / 64 seconds, and 1 hour is 32 seconds / 64 seconds. The energization rate corresponding to each amount of cooked rice is set.

  When the inner pot 2 is induction-heated at the energization rate determined from the amount of rice cooked as described above, the control means 31 continues to count the time being taken from the start of the rice cooking process, and boiling of the cooked rice is detected. Determine whether or not. On the other hand, the boiling determination means 32 determines whether or not the detected temperature of the lid temperature sensor 19 has reached a predetermined temperature (for example, 90 ° C.), and the cooked rice has boiled when the detected temperature reaches the predetermined temperature. The control unit 31 is notified of the determination.

  As shown in FIG. 3, the temperature detected by the bottom temperature sensor 10 rises to around 100 ° C. in a short time from the start of the rice cooking process, which is due to partial boiling of the cooked rice at the bottom of the inner lid 2. . At this time, the whole cooked rice is not yet in a boiling state, and it is not reliable to determine boiling based only on the temperature detected by the bottom temperature sensor 10. On the other hand, the temperature detected by the lid temperature sensor 19 gradually rose after the start of the rice cooking process, the cooked rice started boiling, steam was generated vigorously, and the inner pot 2 was filled with water vapor. Sometimes it begins to rise rapidly. Therefore, it becomes possible to accurately determine the boiling of the whole cooked rice by capturing a sudden rise in the temperature detected by the lid temperature sensor 19.

  On the other hand, when the boiling determination means 32 detects boiling of the cooked rice, the control means 31 determines the amount of rice cooking as described above based on the elapsed time T2 (not shown) from the start of the rice cooking process to the boiling detection. And the electricity supply rate of the induction coil 6 is determined from this rice cooking amount. For example, when T2 is 750 seconds or more, it is determined to be 10 go, and when it is 350 seconds or less, it is determined to be 1 go, and the interval is divided according to the characteristics for each amount of cooked rice. The range of the value of T2 is determined to determine the amount of rice cooking. The energization rate of the induction coil 6 is to ensure that the time from the start of the rice cooking process to the end of the steaming process is ensured for complete gelatinization of the rice, to eliminate the spilling, and to start the rice cooking process It is set for each rice cooking amount on the condition that the time from the end to the end is substantially constant regardless of the rice cooking amount.

  The control means 31 continues the induction heating at the energization rate determined by the determination of the amount of rice cooked, the water in the inner pot 2 disappears, the temperature of the bottom of the inner pot 2 rises rapidly, and the temperature detected by the bottom temperature sensor 10 is the rice cooking temperature. When the temperature reaches the completion temperature (for example, 124 ° C.), the induction coil 6 is turned off to stop induction heating of the inner pot 2 and shift to the steaming process.

  In the steaming step, time measurement is started for a certain time (for example, 12 minutes), waits for the detected temperature of the bottom temperature sensor 10 to drop to a predetermined temperature (for example, 110 ° C.), and when 110 ° C. is detected, the induction coil is again detected. 6 is energized and induction heating is continued until it reaches 124 ° C. And when 124 degreeC is detected, electricity supply to the induction coil 6 is turned off, heating is stopped, and a steaming process is complete | finished when predetermined time passes.

Subsequently, the operation at the time of deterioration due to long-term use will be described by taking as an example a case where the attachment of the lid temperature sensor 19 is lifted by heating of the lid heater 15 or the like.
About the operation | movement until the detection temperature of the bottom temperature sensor 10 becomes 88 degreeC in a preheating process and a rice cooking process, it is the same as that of the rice cooking operation | movement of initial use as mentioned above. However, the detected temperature of the lid temperature sensor 19 cannot accurately detect the ambient temperature in the inner pot 2 due to problems such as floating of the lid temperature sensor 19 and the initial temperature as shown in FIG. It becomes even more gradual.

  When the whole cooked rice starts to boil, steam is generated vigorously and the inner pot 2 is filled with water vapor, the temperature detected by the lid temperature sensor 19 is about to rise rapidly. There is a problem that the ambient temperature in the inner pot 2 cannot be accurately captured. When the detected temperature of the lid temperature sensor 19 detects a predetermined temperature (for example, 90 ° C.) and the boiling of the cooked rice is determined, the process proceeds to the next step. Will be very late compared to the initial use.

  Moreover, the amount of rice cooking is determined based on the elapsed time T2 (not shown) from the start of a rice cooking process to boiling detection similarly to the above, and the electricity supply rate of the induction coil 6 in the next process is determined. In this case, the elapsed time of T2 is longer than that at the time of initial use, and the determination result of the amount of cooked rice is determined more than the actual amount of cooked rice. For example, in the initial use, when the actual amount of cooked rice is 8 go and T2 is 600 seconds, when deteriorated, T2 is 800 seconds, and the determination result of the cooked rice amount is 750 seconds or more, so it is determined to be 10 go. It will be.

Here, determination of the presence or absence of abnormality of the rice cooker according to Embodiment 1 will be described with reference to FIGS.
FIG. 4 is a flowchart showing an operation for determining the presence / absence of abnormality of the rice cooker according to the first embodiment, and FIG. 5 is a flowchart showing an operation of the determination processing of presence / absence of abnormality in FIG. First, description will be made based on the flowchart of FIG. 4, and next, description will be made based on the flowchart of FIG. In addition, execution of the flowchart of FIG.4 and FIG.5 is performed for every rice cooking amount.

  First, the control means 31 is initialized (S1). Next, N of the counter for counting rice cooking set for each rice cooking amount is initialized to 1, and a variable t0 'prepared for each rice cooking amount is initialized to 0 (S2). The t0 'is a variable for determining the total time t0 from the start of cooking (start of the preheating process) to the detection of boiling. Then, the control means 31 performs the rice cooking process which starts from a preheating process, when ON of a rice cooking key is detected as mentioned above. Then, when boiling of the cooked food is detected by the boiling determination means 32 during the rice cooking process, the time t0 from the start of cooking to the detection of boiling is acquired (S3). Next, the acquired time t0 is temporarily stored in the data storage unit 34 in association with the amount of rice cooking as t1 (S4). As described in FIG. 3, the above-mentioned rice cooking amount is determined based on the time until the detected temperature of the bottom temperature sensor 10 reaches 88 ° C. from the start of the rice cooking process.

  Then, the control means 31 determines whether N of the counter corresponding to the rice cooking amount determined previously is, for example, 10 or less (S5), and since N = 1 at this time, the previously acquired time t0 is determined. The total time t0 ′ is calculated by adding to the variable t0 ′, and is stored in the data storage unit 34 in association with the amount of cooked rice (S6). Further, the total time t0 'is divided by N to calculate an average time t0 (average value), which is stored in the data storage unit 34 in association with the amount of cooked rice (S7). Then, an instruction for determining whether or not there is an abnormality is issued to the abnormality determining means 33. When the abnormality determination unit 33 detects the instruction, the abnormality determination unit 33 reads the time t1 and the average time t0 associated with the previous rice cooking amount from the data storage unit 34, and enters an abnormality determination process (S8). This process will be described later with reference to FIG. On the other hand, when the determination result of the abnormality determination unit 33 is normal, the control unit 31 adds 1 to the counter N (S9), returns to S3, and waits until detecting the next rice cooking key ON.

  The above-described operations of S3 to S9 are repeatedly performed for each amount of cooked rice and until N of the counter that is the number of times of cooking reaches 10. In that case, every time rice is cooked, time t0 from the start of rice cooking to boiling detection is set to t1 (S4), and the total time t0 ′ and average time t0 are calculated until the number of times of rice cooking is repeated 10 times in the same amount of rice cooking ( S6, S7). When the number of cooked rices is 11 times or more with the same amount of cooked rice, the process proceeds from S5 to S8, and the abnormality presence / absence determination process starts.

Next, the abnormality presence / absence determination process will be described with reference to FIG.
When the abnormality determination unit 33 detects the abnormality determination instruction from the control unit 31, the time t1 and the average time t0 associated with the rice cooking amount determined during the rice cooking process are read from the data storage unit 34, and further A constant a (predetermined value) associated with the amount of cooked rice is read from the comparison value storage unit 35, added to the average time t0 (t0 + a), and compared with the previous time t1 (S21). When the time t1 is equal to or less than t0 + a (when it is within the predetermined range), it is determined as normal (S25), and the information is notified to the control means 31.

  The above-mentioned constant a is to set how much the characteristic deviation from the boiling detection characteristic at the time of initial use is judged as an abnormal state. For example, when the average time t0 of the time t0 from the start of rice cooking to the boiling detection at the time of rice 5 go in initial use is 400 seconds, if the constant a set for the rice 5 go is 500 seconds When the time t1 is longer than 900 seconds, the abnormal state is determined. Moreover, the constant a can be made arbitrary, such as setting the limit which can ensure the minimum quality as a rice cooker to the extent which deteriorates a rice cooking characteristic and a heat retention characteristic. In other words, if there is more characteristic change than this, it will not be possible to cook delicious rice, and the heat-retaining state will deteriorate, causing abnormal overheating, and there is a risk of smoke and fire.

  On the other hand, the control means 31 continues a rice cooking process, when the information of a normal determination is detected (S26). That is, the rice cooking process is continued until the detected temperature of the bottom temperature sensor 10 reaches the rice cooking completion temperature (124 ° C.), and when the rice cooking completion temperature is detected, the steaming process is started. To complete. And a normal heat retention process is performed (S27). Thereafter, as described above, 1 is added to N of the counter associated with the amount of cooked rice (S9), and the process returns to S3 and waits until the next cooked rice key is detected. The above-described heat retention process is continued until a cancel key provided on the operation panel 16 is turned on.

  Further, the abnormality determining unit 33 determines that the time t1 is longer than t0 + a in S21 (out of a predetermined range) (S22), and notifies the control unit 31 of the information. When detecting the abnormality determination information, the control means 31 ends the rice cooking operation (S23), displays that the liquid crystal display unit 16a is in an abnormal state, and is in an abnormal state by a buzzer (not shown). Announcement is made with sound (S24).

  As described above, according to the first embodiment, the temperature sensing portion of the lid temperature sensor 19 is generated by cooking during actual use, heating during heat retention, humidification by steam generated during rice cooking or moisture adhering to the inner pot 2, or the like. It becomes possible to determine the deterioration of the rice cooking performance and the heat retaining performance due to mounting problems such as floating from the top. As a result, it is possible to prevent in advance problems such as being unable to cook delicious rice or becoming unsavory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.

  In the first embodiment, the same amount of cooked rice is repeated 10 times during initial use, but is not limited to the number of times and may be less than 10 times or 11 times or more. Moreover, although the average time t0 of the time from the rice cooking start to boiling detection when repeating rice cooking 10 times was used as data for the presence or absence of abnormality, it is not restricted to this, For example, predetermined number of times The average time t0 may be obtained from each time t0 obtained in the remaining six times except for the first and second times, and the ninth and tenth times. By doing so, it can be used as more reliable data (average time t0).

  Moreover, in Embodiment 1, although the abnormality determination process by the abnormality determination means 33 was performed immediately after the boiling detection in a rice cooking process, it is not restricted to this, For example, at the time of the end of rice cooking where a steaming process is complete, Alternatively, the process may be performed when the heat retaining process is completed and the mode is shifted to the cancel mode. In this case, when cooking is completed, an abnormality determination is performed. When it is determined that the state is abnormal, the operation is automatically stopped without shifting to the heat retaining step, and the liquid crystal display unit 16a is informed that the state is abnormal. Announces via buzzer. Similarly, when the abnormality determination is performed at the end of the heat insulation process, the abnormality state is notified through the liquid crystal display unit 16a and the buzzer in the cancel mode.

  Furthermore, although the case where attachment of the lid temperature sensor 19 has floated due to heating of the lid heater 15 or the like has been described as an example, attachment of the heaters 4 and 15 provided on the side surface radiator plate 5 or the lid radiator plate 14, Since the characteristic change of the boiling detection also occurs due to the malfunction of the induction coil 6, it is possible to detect the presence or absence of abnormality in the same manner.

Embodiment 2. FIG.
In Embodiment 1, when the boiling of the cooked rice is detected via the lid temperature sensor 19, the presence or absence of abnormality of the lid temperature sensor 19 is determined based on the time t0 (t1) from the start of cooking to the detection of boiling. However, in Embodiment 2, when the boiling of the cooked rice is detected via the bottom temperature sensor 10, the presence or absence of abnormality of the bottom temperature sensor 10 is determined based on the time t0 (t1) from the start of cooking to the detection of boiling. It is what you do.
The rice cooker according to the second embodiment has the same configuration as the rice cooker according to the first embodiment except that the boiling determination means 32 performs a boiling determination method for the cooked food. Hereinafter, the rice cooker of Embodiment 2 is demonstrated using FIG. In addition, the same code | symbol is attached | subjected to the part similar to Embodiment 1. FIG.

  FIG. 6: is a figure which shows the correlation of the temperature curve and rice cooking power in the rice cooking operation | movement of the rice cooker which concerns on Embodiment 2 of this invention. In addition, the temperature curve in a figure is a temperature change of the inner pot 2 bottom part by the detection of the bottom temperature sensor 10, and shows the temperature change at the time of initial use and the temperature change at the time of malfunction occurrence (during deterioration) by long-term use. . The description of the defect is the same as in the first embodiment.

Here, operation | movement until it acquires time t0 (t1) from a rice cooking start to boiling detection is demonstrated, referring FIG. In addition, since the operation | movement of a preheating process is the same as that of Embodiment 1, it demonstrates from operation | movement of a rice cooking process.
When the control means 31 of the control circuit 30 enters the rice cooking process, the induction coil 6 is energized continuously as described above to inductively heat the inner pot 2. At this time, the temperature detected by the bottom temperature sensor 10 starts to rise rapidly as shown in the figure. On the other hand, the boiling determination means 32 calculates a temperature change value per unit time based on the temperature detected by the bottom temperature sensor 10 and compares it with a preset increase value. This increase value is set corresponding to the amount of cooked rice. For example, the change value of the detected temperature of the bottom temperature sensor 10 in unit time 60 seconds is compared with the increase value 5K. When the change value is smaller than 5K, it is determined that the boiling has occurred, and this is notified to the control means 31. When receiving the notification, the control means 31 stores the time t0 from the start of cooking (start of the preheating process) to the detection of boiling in the data storage unit 34 in association with the amount of cooking rice. This series of operations is repeated 10 times for each amount of cooked rice.

  On the other hand, if there is a problem such as the temperature sensing part of the bottom temperature sensor 10 floating from the bottom of the inner pot 2 due to long-term use, the bottom temperature sensor 10 accurately determines the temperature of the cooked rice in the inner pot 2. As a result, the temperature curve becomes very gentle as shown in the figure. In such a case, the boiling detection by the boiling determination means 32 is detected very late with respect to the initial use as shown in FIG. The time from the start of rice cooking to the detection of boiling during this deterioration is t1 longer than t0. The process for averaging the time t0 for each amount of cooked rice and the process for determining the presence or absence of abnormality by comparing the average time t0 (+ a) with the time t1 are the same as in the case of the first embodiment.

As described above, even a rice cooker configured to detect boiling only with temperature information from the bottom temperature sensor 10 can detect a change in temperature characteristics due to deterioration of the bottom temperature sensor 10, and thus cooks delicious rice. It is possible to prevent in advance problems such as inability to cook or unsatisfactory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.
In addition, although the rice cooker of Embodiment 2 is a structure which detects a boiling only by the temperature information of the bottom temperature sensor 10, as mentioned above, it is judged that the boiling of rice cooked is based on the change value of the temperature per unit time. Therefore, the reliability of boiling detection is ensured.

Embodiment 3 FIG.
In the first and second embodiments, the timing base point at time t0 (t1) is set to start rice cooking, but in the third embodiment, when the temperature detected by the bottom temperature sensor 10 reaches a predetermined temperature, the time t0 (t1) The timing is started.
The rice cooker of Embodiment 3 is the same structure as the rice cooker of Embodiment 1, and hereafter, the rice cooker of Embodiment 3 is demonstrated using FIG. In addition, the same code | symbol is attached | subjected to the part similar to Embodiment 1. FIG.

  FIG. 7: is a figure which shows the correlation of the temperature curve and rice cooking power in the rice cooking operation | movement of the rice cooker which concerns on Embodiment 3 of this invention. In addition, the temperature curve of the continuous line shown in a figure shows the temperature change of the inner pot 2 bottom part by the detection of the bottom temperature sensor 10, and the temperature curve of a broken line shows the change of the atmospheric temperature in the inner pot 2 by the detection of the lid temperature sensor 19. Show. Moreover, among the temperature curves of the lid temperature sensor 19 indicated by a broken line, one curve is a temperature change at the initial use of the rice cooker, and the other curve is a temperature change at the time of occurrence of a malfunction (during deterioration) due to long-term use. It is. The description of the defect is the same as in the first embodiment.

  Here, the operation until the time t0 (t1) is acquired will be described with reference to FIG. The operation of the preheating process, the operation from the start of rice cooking for initial use to the detection of boiling by the lid temperature sensor 19, and the operation from the detection of boiling at the time of long-term deterioration are the same as in the first embodiment.

  When the temperature detected by the bottom temperature sensor 10 reaches a predetermined temperature (for example, 88 ° C.) in the rice cooking process, the control means 31 starts measuring the time for acquiring the time t0 (t1). On the other hand, the boiling determination unit 32 determines whether the cooked rice has boiled (for example, 90 ° C.) from the detection temperature of the lid temperature sensor 19, and notifies the control unit 31 when it has detected boiling of the cooked rice. When receiving the notification, the control means 31 acquires a time t0 (t1) from the detection of the predetermined temperature to the boiling detection. This series of operations is repeated 10 times for each amount of cooked rice. And the process of averaging the time t0 for each amount of cooked rice and the process of determining the presence or absence of abnormality by comparing the average time t0 (+ a) and the time t1 are the same as in the case of the first embodiment.

  The time from the predetermined temperature based on the temperature detected by the bottom temperature sensor 10 to the boiling detection based on the determination by the boiling determination means 32 is often used for determining the amount of rice cooked by a general rice cooker. When the rice cooking amount determination time is out of the predetermined time range, it is determined that the product is abnormal. By determining an abnormality and stopping or notifying the operation, a change in characteristics due to deterioration can be detected, and the same effect as in the first embodiment can be obtained. The range of the predetermined time set here should be a value derived from conditions that can ensure minimum quality as a rice cooker.

  In the third embodiment, by setting the base point of the time until the boiling is detected by the lid temperature sensor 19 from the predetermined temperature detected by the bottom temperature sensor 10, the lid temperature sensor 19 is abnormal due to the deterioration of the parts. For the problems that occur, it is possible to obtain the same effect as in the first embodiment by detecting a change in temperature characteristics due to deterioration. Further, even if the lid temperature sensor 19 is not abnormal and the bottom temperature sensor 10 is abnormal, the same effect can be obtained if the abnormal state is determined by being out of the predetermined time range. it can.

Embodiment 4 FIG.
FIG. 8 is a block diagram showing the configuration of the rice cooker according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the part similar to Embodiment 1 demonstrated in FIG.1 and FIG.2.
In the rice cooker shown in FIG. 8, when the control means 31 detects boiling of the cooked food via the boiling determination means 32 during the rice cooking process, the control means 31 obtains the time t0 from the start of rice cooking until the boiling detection to t1, and the information Is notified to the abnormality determination means 33. When the time t1 is input, the abnormality determination unit 33 reads a constant b (predetermined value) stored in the comparison value storage unit 35 in advance and compares it with the time t1, and determines whether there is an abnormality based on the result. To do. The constant b preserve | saved at the comparison value memory | storage part 35 is an upper limit which can ensure minimum quality as a rice cooker, and is set according to the characteristic of the rice cooker, the amount of rice cooking, etc.

  Next, in the rice cooker of Embodiment 4, the abnormality presence / absence determination process will be described with reference to the flowchart of FIG. FIG. 9 is a flowchart showing an operation for determining whether there is an abnormality in the rice cooker according to the fourth embodiment. In addition, the temperature curve and rice cooking electric power in rice cooking operation | movement are the same as that of Embodiment 1 demonstrated in FIG.

  When the rice cooking process is performed by the control means 31, the boiling determination means 32 determines whether the cooked rice has boiled based on the detection temperature of the lid temperature sensor 19, and the detection temperature of the lid temperature sensor 19 reaches the boiling temperature. When it does, it determines with the cooked rice having boiled, and notifies that to the control means 31. On the other hand, when the control means 31 receives the notification, the control means 31 obtains a time t0 from the start of cooking rice to the detection of boiling as t1, and notifies the abnormality determination means 33 of the time.

  At this time, the abnormality determination means 33 reads the constant b stored in the comparison value storage unit 35, that is, the constant b set corresponding to the amount of cooked rice, and compares it with the previous time t1 (S31). When the time t1 is less than or equal to the constant b, it is determined as normal (S35), and the information is notified to the control means 31. The control means 31 continues the rice cooking process when detecting normality determination information (S36). That is, the rice cooking process is continued until the detected temperature of the bottom temperature sensor 10 reaches the rice cooking completion temperature (124 ° C.), and when the rice cooking completion temperature is detected, the steaming process is started. To complete. Then, the normal heat retaining process is continued until the cancel key provided on the operation panel 16 is turned on (S37).

  Further, when it is determined that the time t1 is longer than the constant b in S31, the abnormality determination unit 33 determines that there is an abnormality (S32) and notifies the control unit 31 of the information. When detecting the abnormality determination information, the control means 31 terminates the rice cooking operation (S33), displays the abnormal state on the liquid crystal display unit 16a, and indicates that the abnormal state is detected by a buzzer (not shown). A sound is notified (S34). By this notification, you can know in advance that you will not be able to cook delicious rice, that the heat insulation state will worsen and the rice will not be delicious, and that abnormal overheating will occur and the risk of smoke and ignition in advance Can know.

As described above, according to the fourth embodiment, the time t0 (t1) from the start of rice cooking to the detection of boiling obtained every time rice is cooked is compared with the constant b stored in the comparison value storage means 33. Since the presence / absence of abnormality is determined, the data storage means 32 provided in the rice cooker according to the first, second, and third embodiments is unnecessary, and a change in temperature characteristics due to deterioration of parts is detected with a simple configuration. Therefore, it is possible to prevent in advance problems such as the inability to cook delicious rice or the unsavory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.
Further, since the process of averaging from the acquisition of the time t0 until the boiling detection at the initial use is not required as shown in FIG. 4 of the first embodiment, the control program executed by the control means 31 is simplified. It is possible to provide a cheaper and safer rice cooker.

  In the fourth embodiment, when the detected temperature of the lid temperature sensor 19 reaches the boiling temperature, the time t0 (t1) from the start of cooking to the detection of boiling is obtained. You may make it acquire time t0 (t1) from the start of rice cooking for the comparison with the constant b using the bottom temperature sensor 10 to boiling detection like the form 2. FIG. Further, as in the third embodiment described with reference to FIG. 7, a time t0 (t1) from when a predetermined temperature is reached until boiling is detected in order to compare with the constant b using the bottom temperature sensor 10 and the lid temperature sensor 19. May be acquired (however, the average value is not calculated).

Embodiment 5 FIG.
In Embodiments 1-4, although it is a rice cooker provided with bottom temperature sensor 10 and lid temperature sensor 19, Embodiment 5 is a rice cooker provided only with bottom temperature sensor 10.
FIG. 10 is a block diagram showing the configuration of the rice cooker according to Embodiment 5 of the present invention.

  In the rice cooker of the fifth embodiment, as described in the second embodiment (see FIG. 6), the boiling determination means 32 is unit time (for example, 60 seconds) depending on the detected temperature of the bottom temperature sensor 10 during rice cooking. A change value of the hit temperature is calculated and compared with a preset increase value of 5K. This increase value is set corresponding to the amount of cooked rice. When the change value of the detected temperature of the bottom temperature sensor 10 is smaller than 5K, it is determined as boiling, and this is notified to the control means 31. When receiving the notification, the control means 31 stores the time t0 from the start of cooking (start of the preheating process) to the detection of boiling in the data storage unit 34 in association with the amount of cooking rice. This series of operations is repeated 10 times for each amount of cooked rice.

  On the other hand, if there is a problem such as the temperature sensing part of the bottom temperature sensor 10 floating from the bottom of the inner pot 2 due to long-term use, the bottom temperature sensor 10 accurately determines the temperature of the cooked rice in the inner pot 2. It becomes impossible to detect, and as shown in FIG. 6, it becomes a very gentle temperature curve. In such a case, the boiling detection by the boiling determination means 32 is detected very late with respect to the initial use as shown in FIG. The time from the start of rice cooking to the detection of boiling during this deterioration is t1 longer than t0. The process for averaging the time t0 for each amount of cooked rice and the process for determining the presence or absence of abnormality by comparing the average time t0 (+ a) with the time t1 are the same as in the case of the first embodiment. In the present embodiment, the boiling detection is performed only by the temperature information of the bottom temperature sensor 10, but since the determination is made based on the change value of the detected temperature, the reliability of the boiling detection is ensured. .

  As described above, in the fifth embodiment, even a rice cooker configured to detect boiling only with temperature information of the bottom temperature sensor 10 can detect a change in temperature characteristics due to deterioration of the bottom temperature sensor 10. It is possible to prevent in advance problems such as being unable to cook delicious rice or becoming unsavory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.

Embodiment 6 FIG.
In the rice cooker having only the bottom temperature sensor 10, the sixth embodiment is similar to the fourth embodiment (see FIG. 9), and the time t 0 (t 1) until the boiling detection obtained every time rice is cooked and the constant b And the presence or absence of an abnormality is determined based on the result.
FIG. 11 is a block diagram showing a configuration of a rice cooker according to Embodiment 6 of the present invention. In addition, the same code | symbol is attached | subjected to the part similar to Embodiment 4 demonstrated in FIG. Also, the abnormality presence / absence determination processing in the sixth embodiment is the same as the flowchart of FIG.

  In the rice cooker of the sixth embodiment, as described in the fifth embodiment, the boiling determination means 32 is a temperature change value per unit time (for example, 60 seconds) depending on the temperature detected by the bottom temperature sensor 10 during rice cooking. Is calculated and compared with a preset increase value of 5K. This increase value is set corresponding to the amount of cooked rice. When the change value of the detected temperature of the bottom temperature sensor 10 is smaller than 5K, it is determined as boiling, and this is notified to the control means 31. The control means 31 acquires the time t0 from the start of rice cooking (start of the preheating process) to the boiling detection when receiving the notification, and notifies the abnormality determination means 33 as t1.

  At this time, the abnormality determination means 33 reads the constant b stored in the comparison value storage unit 35, that is, the constant b set corresponding to the amount of cooked rice, and compares it with the previous time t1 (S31). When the time t1 is less than or equal to the constant b, it is determined to be normal (S35), the information is notified to the control means 31, and the rice cooking process is continued. In addition, about the detection of the rice cooking completion temperature in a rice cooking process, the operation | movement of a steaming process, and a heat retention process, it is the same as that of Embodiment 4 (S36, S37).

  Further, the abnormality determining means 33 determines that the time t1 is longer than the constant b in S31 (when it is outside the predetermined range) (S32), and notifies the control means 31 of the information. When detecting the abnormality determination information, the control means 31 terminates the rice cooking operation (S33), displays the abnormal state on the liquid crystal display unit 16a, and indicates that the abnormal state is detected by a buzzer (not shown). A sound is notified (S34). In the present embodiment, as described above, the boiling detection is performed only by the temperature information of the bottom temperature sensor 10, but since the determination is made based on the change value of the detected temperature, the reliability of the boiling detection is determined. Is secured.

As described above, in Embodiment 6, even a rice cooker configured to detect boiling only with temperature information of the bottom temperature sensor 10 can detect a change in temperature characteristics due to deterioration of the bottom temperature sensor 10. It is possible to prevent in advance problems such as being unable to cook delicious rice or becoming unsavory rice with poor heat retention. In addition, it is possible to prevent in advance the risk of smoke or fire due to overheating due to temperature detection failure.
Further, since the process of averaging from the acquisition of the time t0 until the boiling detection at the initial use is not required as shown in FIG. 4 of the first embodiment, the control program executed by the control means 31 is simplified. It is possible to provide a cheaper and safer rice cooker.

  In the description of the operation of the first to sixth embodiments, the case where t1 is longer than the time t0 is taken as an example. However, the present invention is not limited to this, and the change in characteristics due to the constant change of the electrical components. In this case, the time t1 may be shorter than t0. In that case, in the determination of S21 in the flowchart of FIG. 5 of the first embodiment, the constant a takes a negative value and is compared by a comparison formula of “t1 ≧ t0 + a”, and in the flowchart of FIG. 9 of the fourth embodiment. In the determination of S31, the comparison is made using the comparison formula “t1 ≧ b”.

  As described above, the configuration and operation of the present invention are not limited to these, and can be appropriately modified and implemented without departing from the scope of the invention.

It is sectional drawing which shows the structure of the rice cooker which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the rice cooker which concerns on Embodiment 1. FIG. It is a figure which shows the correlation of the temperature curve and rice cooking power in the rice cooking operation | movement of the rice cooker which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation | movement for determining the abnormality presence or absence of the rice cooker which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation | movement of the determination process of the presence or absence of abnormality in FIG. It is a figure which shows the correlation of the temperature curve and rice cooking power in the rice cooking operation | movement of the rice cooker which concerns on Embodiment 2 of this invention. It is a figure which shows the correlation of the temperature curve and rice cooking power in the rice cooking operation | movement of the rice cooker which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the rice cooker which concerns on Embodiment 4 of this invention. It is a flowchart which shows the operation | movement for determining the abnormality presence or absence of the rice cooker which concerns on Embodiment 4. FIG. It is a block diagram which shows the structure of the rice cooker which concerns on Embodiment 5 of this invention. It is a block diagram which shows the structure of the rice cooker which concerns on Embodiment 6 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Inner pan, 6 Inductive coil, 7 Coil stand, 10 Bottom temperature sensor, 11 Spring, 12 Lid body, 16a Liquid crystal display part, 16b Key input part, 19 Lid temperature sensor, 30 Control circuit, 31 Control means, 32 boiling determination means, 33 abnormality determination means, 34 data storage section, 35 comparison value storage section.

Claims (10)

An inner pot for storing cooked rice,
Heating means for heating the inner pot;
A lid temperature sensor for detecting the temperature in the inner pot;
A bottom temperature sensor for detecting the temperature of the bottom of the inner pot;
Control means for controlling the heating means according to a preset program and cooking the cooked rice in the inner pot,
Boil determining means for determining boiling of the cooked rice in the inner pot from the detection temperature of the lid temperature sensor each time rice is cooked by the control means;
An abnormality determination means for determining the presence or absence of abnormality of the rice cooker body,
The control means acquires the time from the start of cooking to the detection of boiling every time boiling of the cooked food is detected by the boiling determination means, and calculates the average value from the acquired time,
The rice cooker characterized in that the abnormality determining means determines that there is an abnormality when a difference between the time and the average value is out of a predetermined range. The boiling determination means, wherein in place of the lid temperature sensor, to determine the boiling of rice of the temperature detected or found before Symbol inner bowl of the bottom temperature sensor each time cooking is performed by the control means,
The control means acquires the time from the start of cooking to the detection of boiling every time boiling of the cooked food is detected by the boiling determination means, and calculates the average value from the acquired time,
The rice cooker according to claim 1, wherein the abnormality determining means determines that there is an abnormality when a difference between the time and the average value is out of a predetermined range.
Each time the control means detects the boiling of the cooked rice by the boiling determination means, the control means acquires the time until the boiling detection based on the predetermined temperature detected by the bottom temperature sensor before that, and the acquired time Calculate the average value from
The rice cooker according to claim 1, wherein the abnormality determining means determines that there is an abnormality when a difference between the time and the average value is out of a predetermined range. An inner pot for storing cooked rice,
Heating means for heating the inner pot;
A bottom temperature sensor for detecting the temperature of the bottom of the inner pot;
Control means for controlling the heating means according to a preset program and cooking the cooked rice in the inner pot,
Boil determining means for determining boiling of the cooked rice in the inner pot from the detection temperature of the bottom temperature sensor each time rice is cooked by the control means;
An abnormality determination means for determining the presence or absence of abnormality of the rice cooker body,
The control means acquires the time from the start of cooking to the detection of boiling every time boiling of the cooked food is detected by the boiling determination means, and calculates the average value from the acquired time,
The rice cooker characterized in that the abnormality determining means determines that there is an abnormality when a difference between the time and the average value is out of a predetermined range.   5. The rice cooker according to claim 1, wherein the control means calculates the average value until the average value is repeated a predetermined number of times for each amount of rice cooked. An inner pot for storing cooked rice,
Heating means for heating the inner pot;
A lid temperature sensor for detecting the temperature in the inner pot;
A bottom temperature sensor for detecting the temperature of the bottom of the inner pot;
Control means for controlling the heating means according to a preset program and cooking the cooked rice in the inner pot,
Boil determining means for determining boiling of the cooked rice in the inner pot from the detection temperature of the lid temperature sensor each time rice is cooked by the control means;
An abnormality determination means for determining the presence or absence of abnormality of the rice cooker body,
The control means, when boiling of the cooked rice is detected by the boiling determination means, acquires the time from the start of cooking to the detection of boiling,
The rice cooker according to claim 1, wherein the abnormality determination means determines that there is an abnormality when the time is out of a predetermined range. The boiling determination means determines boiling of the cooked rice in the inner pot from the detected temperature of the bottom temperature sensor every time rice is cooked by the control means instead of the lid temperature sensor,
The control means, when boiling of the cooked rice is detected by the boiling determination means, acquires the time from the start of cooking to the detection of boiling,
The rice cooker according to claim 6, wherein the abnormality determination means determines that there is an abnormality when the time is out of a predetermined range. When the boiling means of the cooked rice is detected by the boiling determination means, the control means acquires the time until the boiling detection based on the predetermined temperature detected by the bottom temperature sensor before that,
The rice cooker according to claim 6, wherein the abnormality determination means determines that there is an abnormality when the time is out of a predetermined range. An inner pot for storing cooked rice,
Heating means for heating the inner pot;
A bottom temperature sensor for detecting the temperature of the bottom of the inner pot;
Control means for controlling the heating means according to a preset program and cooking the cooked rice in the inner pot,
Boil determining means for determining boiling of the cooked rice in the inner pot from the detection temperature of the bottom temperature sensor each time rice is cooked by the control means;
An abnormality determination means for determining the presence or absence of abnormality of the rice cooker body,
The control means, when boiling of the cooked rice is detected by the boiling determination means, acquires the time from the start of cooking to the detection of boiling,
The rice cooker according to claim 1, wherein the abnormality determination means determines that there is an abnormality when the time is out of a predetermined range.   The said predetermined range is set corresponding to the amount of rice cooking, The rice cooker in any one of Claim 1 thru | or 9 characterized by the above-mentioned.

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